The psychosocial dimension of prostate cancer has received increased attention over the past 2 decades. The objectives of the study were to investigate the men's psychosocial adjustment over the course of the first year of prostate cancer and to examine the sense of coherence, couple cohesion and adaptability, sexual and urinary symptoms, and mood disturbance as predictors of their adjustment. There were 81, 69, and 61 men visited at home prior to treatment (T1), 3 months later (T2), and 1 year after the first visit (T3), respectively. Repeated-measures analyses of variance were used to examine adjustment over time. Multiple regressions determined whether the predictors were associated with the adjustment domains. Sexual relationship deteriorated and social environment improved between T1 and T2. Between T1 and T3, sexual, domestic, and family relationships deteriorated, whereas social environment improved. Mood disturbance, sense of coherence, couple cohesion, and couple adaptability were predictors of psychological, vocational, and domestic domains at T1. At T2, mood disturbance and sexual functioning were predictors of healthcare, vocational, social, psychological, and family domains. At T3, couple cohesion and adaptability and urinary functioning were predictors to vocational, domestic, social, and psychological adjustment. During the first year of prostate cancer, men showed deterioration in sexual, close-family, and extended-family relationship domains. Sexuality is an important topic, and spousal communication should be encouraged throughout the first year following diagnosis. Preparedness for the changes associated with prostate cancer along with continuing support to couples, rather than to patients only, might be the strongest approach to enhancing men's adjustment.